There are many scenarios in which individuals desire to limit or otherwise control access to assets. For example, individuals may desire to control access to data stored on a smart phone or other portable electronic device, to locations secured by door locks or other mechanisms, to industrial equipment for use only by authorized personnel, to firearms or controlled substances, etc. A number of physical and logical access controls are available for such scenarios, including keys, passwords, credentials, etc. Increasingly, individuals and organizations are seeking biometric solutions for access control. However, traditional biometric detection systems can be too large, expensive, unreliable, and/or otherwise undesirable to implement in many contexts.
In particular, traditional optical biometric approaches tend to be too large to implement in a miniaturized form factor and/or too expensive to implement in commodity-type consumer goods (e.g., integrated into a smart phone, a door lock, an industrial equipment button, etc.). Further, traditional approaches (especially smaller and less expensive approaches) tend to have limited reliability across wide operating conditions, such as with high variability in finger skin wetness or dryness, ambient lighting conditions, etc.; and/or limited ability to distinguish between a genuine skin site and a spoof (any of a variety of means and materials presented to the sensor in an attempt to replicate a genuine finger and thereby defeat the security of the system).